1. SPECTS 2012, Genoa, 10th July 2012Traffic Optimization for TCP-based Massive Multiplayer Online Games Jose Saldana Luis Sequeira Julin Fernndez-Navajas Jos Ruiz-Mas Communication Technologies Group (GTC) Aragon Inst. of Engineering Research (I3A) University of Zaragoza

2. SPECTS 2012, Genoa, 10th July 2012Index 1. 2. 3. 4. 5.Introduction Related Works Analysis of TCM for MMORPG games Tests and Results Conclusions 3. SPECTS 2012, Genoa, 10th July 2012Index 1. 2. 3. 4. 5.Introduction Related Works Analysis of TCM for MMORPG games Tests and Results Conclusions 4. SPECTS 2012, Genoa, 10th July 2012Introduction Online games are getting more and more popular MMORPG (Massive Multiplayer Online Role Playing Games) are a specific genre with a set of shared characteristics Number of titles, and number of players growing, especially in Asia 5. SPECTS 2012, Genoa, 10th July 2012Introductionhttp://designcult.org/designcult/2010/08/mmo-subscription-charts.html 6. SPECTS 2012, Genoa, 10th July 2012Introduction Common characteristics: Long-term avatar who can reach higher levels Missions Objects Interaction between real-players High number of players share a scenario The most popular one: World of Warcraft 7. SPECTS 2012, Genoa, 10th July 2012IntroductionWoW video 8. SPECTS 2012, Genoa, 10th July 2012Introduction Differences with First Person Shooters: Session duration is longer Number of player is bigger Real-time requirements are looser They use TCP instead of UDP 9. SPECTS 2012, Genoa, 10th July 2012Introduction Consequences of using TCP: Retransmission when a packet is lost Dependence on the TCP variant More overhead (40 bytes instead of 28) But they are interactive: The speed of the player matters We have a real-time service using TCP!!! 10. SPECTS 2012, Genoa, 10th July 2012Introduction Problem of supporting the game It is difficult to predict the success of a game Players are especially difficult clients: they usually have very high expectations High amounts of bandwidth and processing capacity 11. SPECTS 2012, Genoa, 10th July 2012Introduction 12. SPECTS 2012, Genoa, 10th July 2012Introduction Supporting infrastructures are critical. They MUST work 24/7. Over-provisioning? 13. SPECTS 2012, Genoa, 10th July 2012Introduction Techniques for saving bandwidth can be interesting A reduction in the number of packets per second can also be good 14. SPECTS 2012, Genoa, 10th July 2012Introduction We have long-term flows of small packets which have the same: Source and destination IP Source and destination port Many other header fields that do not change We can use header compression 15. SPECTS 2012, Genoa, 10th July 2012Introduction We also have scenarios in which a number of flows share the same path TCM ProxyCentral Game ServerTCMTCMTCM . . .ProxyPlayersMultiplexerAccess routerPlayersProxy Players We can multiplex these flowsGame Server 16. SPECTS 2012, Genoa, 10th July 2012Introduction We can adapt aTunneling-CompressingMultiplexing technique, deployed for RTP flows, and use it for TCP . . .Context. . .ContextIP Network. . .MUX+COMPReal-TimeDEMUX+DECOMPTunneling-Compressing-MultiplexingReal-Time. . . 17. SPECTS 2012, Genoa, 10th July 2012Index 1. 2. 3. 4. 5.Introduction Related Works Analysis of TCM for MMORPG games Tests and Results Conclusions 18. SPECTS 2012, Genoa, 10th July 2012Related Works Header compression methods They use the repeatibility of header fields in order to avoid sending them Need of a context, shared between origin and destination Importance of context synchronization Need of tunneling Different standards: ECRTP, IPHC, ROHC 19. SPECTS 2012, Genoa, 10th July 2012Related Works TCRTP: Current Tunneling-CompressingMultiplexing standard (RFC4170) Designed for VoIP payloadpayload ECRTP...ECRTPRTP UDP IPPPP Mux PPP L2TP IP 20. SPECTS 2012, Genoa, 10th July 2012Related Works Mean Opinion Score (MOS) Adapted from VoIP to games Ranges from 1 (bad quality) to 5 (excellent) Need of subjective tests Depends on network impairments: delay, loss, jitter 21. SPECTS 2012, Genoa, 10th July 2012Index 1. 2. 3. 4. 5.Introduction Related Works Analysis of TCM for MMORPG games Tests and Results Conclusions 22. SPECTS 2012, Genoa, 10th July 2012TCM for MMORPG traffic We adapt the protocol stack from TCRTPpayloadpayload ECRTP...ECRTPRTP UDPPayloadPayload Reduced Header...IPIP PPP MuxPPP MuxPPPPPPL2TPL2TPIPIPTCRTPTCP Reduced HeaderTCM 23. SPECTS 2012, Genoa, 10th July 2012TCM for MMORPG traffic We adapt the protocol stack from TCRTPpayloadpayload ECRTP...ECRTPRTP UDPPayloadPayload Reduced Header...IPIP PPP MuxPPP MuxPPPPPPL2TPL2TPIPIPTCRTPTCP Reduced HeaderTCM 24. SPECTS 2012, Genoa, 10th July 2012TCM for MMORPG traffic We establish a tunnel to the game server, while multiplexing packets Tretention Tprocess Tqueue. . .MUXTnetworkIP networkTprocessDEMUXGame ServerPlayers IPTCMIP 25. SPECTS 2012, Genoa, 10th July 2012TCM for MMORPG traffic We establish a policy for selecting the packets, using a period Native traffic ...PEPEPET